10101999821 has 2 divisors, whose sum is σ = 10101999822. Its totient is φ = 10101999820.

The previous prime is 10101999779. The next prime is 10101999833. The reversal of 10101999821 is 12899910101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10098240100 + 3759721 = 100490^2 + 1939^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10101999821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10101999871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5050999910 + 5050999911.

It is an arithmetic number, because the mean of its divisors is an integer number (5050999911).

Almost surely, 2^10101999821 is an apocalyptic number.

It is an amenable number.

10101999821 is a deficient number, since it is larger than the sum of its proper divisors (1).

10101999821 is an equidigital number, since it uses as much as digits as its factorization.

10101999821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 41.

The spelling of 10101999821 in words is "ten billion, one hundred one million, nine hundred ninety-nine thousand, eight hundred twenty-one".